Portable Toilet

ABSTRACT

A portable toilet comprises a holding tank and a toilet bowl unit supported above the holding tank. An uppermost wall of the holding tank locates an inlet opening therein which co-operates with a bottom discharge opening of the toilet bowl unit. A valve mechanism is operable across the inlet opening. The uppermost wall of the tank which locates the inlet opening therein is readily removable for greater access to the interior of the holding tank for disposable of the contents of the tank and for cleaning.

This application claims the benefit under 35 U.S.C. 119(e) of U.S.provisional application Ser. No. 60/884,497, filed Jan. 11, 2007.

FIELD OF THE INVENTION

The present invention relates to a portable toilet, and moreparticularly relates to a toilet of the type have a bowl unit comprisinga toilet bowl and flushing reservoir detachably supported above a lowerwaste holding tank.

BACKGROUND

One known type of portable toilet involves a toilet bowl locating areservoir for a flushing liquid therein which is detachably supportedonto a waste holding tank. The holding tank normally supports the bowlunit thereon, but the bowl unit can be separated from the waste holdingtank for servicing or for disposing of the waste within the holdingtank. A flushing mechanism typically delivers the flushing liquid fromthe reservoir into the bowl when flushing. The bowl discharges through adischarge opening in the bottom thereof which communicates with acooperating opening in the holding tank. A valve mechanism in thedischarge opening is normally closed for sealing the holding tank shut;however the valve can be manually opened when discharging the contentsof the toilet bowl into the holding tank.

Prior art designs of holding tanks in toilets of this type typicallyonly include an inlet opening for communication with the dischargeopening of the toilet bowl and which is sealed closed by the valvemechanism, and an outlet opening for emptying the contents of theholding tank. Prior art designs of discharge openings are typically inthe form of a small circular opening enclosed by a threaded cap in aside wall, typically adjacent the bottom of the tank. When locating theopening adjacent the bottom of the tank, such a small opening with athreaded cap is typically required to ensure a proper seal when theoutlet is to be closed for use. The small and limited access provided bythe inlet opening and the outlet opening however make it very difficultto clean the holding tank and remove any materials which may be cloggedtherein.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a portabletoilet comprising:

a bowl unit comprising a toilet bowl with a bottom discharge opening anda reservoir arranged to receive a flushing liquid for flushing thetoilet bowl;

a holding tank arranged to support the bowl unit thereabove, the holdingtank defining a waste holding chamber enclosed by a plurality of wallsections;

an inlet opening in an upper one of the wall sections of the holdingtank which is arranged to co-operate with the discharge opening of thetoilet bowl when the bowl unit is supported on the holding tank suchthat waste material in the toilet bowl is arranged to be receivedthrough the inlet opening into the waste holding chamber; and

a valve mechanism associated with the inlet opening of the holding tank,the valve mechanism comprising a valve member operable across the inletopening between respective open and closed positions;

one of the wall sections of the holding tank comprising a removable wallsection which is selectively separable from remaining ones of the wallsections such that the remaining ones of the wall sections define a wallopening in the holding tank through which waste material in the wasteholding chamber is arranged to be discharged.

According to a second aspect of the present invention there is provideda portable toilet comprising:

a holding tank defining a waste holding chamber surrounded by aplurality of wall sections;

a bowl unit arranged to be supported above the holding tank comprising atoilet bowl with a bottom discharge opening;

an uppermost one of the wall sections of the holding tank comprising aremovable wall section which is selectively separable from remainingones of the wall sections such that the remaining ones of the wallsections define a wall opening in the holding tank spanning the top endof the holding tank through which waste material in the waste holdingchamber is arranged to be discharged;

the uppermost one of the wall sections having an inlet opening thereinwhich is arranged to co-operate with the discharge opening of the toiletbowl when the bowl unit is supported above the holding tank such thatwaste material in the toilet bowl is arranged to be received through theinlet opening into the waste holding chamber; and

a valve mechanism associated with the inlet opening of the holding tank,the valve mechanism comprising a valve member operable across the inletopening between respective open and closed positions.

By providing a removable wall section in the holding tank, a larger areaof the tank can be opened for greater access and ease of cleaning anddischarging the contents of the holding tank. Locating the wall sectionat the top end allows a friction fit over a large area as compared tothe prior art as such a configuration of sealing is generally sufficientwhen locating the opening above fluid levels in the tank. Furthermore noadditional threaded connection and the like is required to effect propersealing as the bowl unit clamped onto the holding tank can also serve toclamp the removable wall section in place by a common clampingmechanism.

By locating the inlet opening in the removable wall section, theresulting walls of the holding tank are smooth and generally flat inprofile to ensure ease of cleaning and to be free of any protrusions andthe like which may be clogged or upon which waste may be caught.Providing a removable wall section also readily permits the use ofliners to be used in the holding tank. The resulting structure of theholding tank having upright walls about the periphery thereof alsoprovides adequate support for supporting the bowl unit thereon about thefull periphery in a stable and strong manner without any additionalintermediate supports and the like being required.

The removable wall section preferably comprises an uppermost one of thewall sections which spans a top end of the holding tank.

More particularly, the inlet opening is preferably located in theremovable wall section in the preferred embodiment.

The removable wall section may be held in a closed position spanning thewall opening by the bowl unit supported on the holding tank. In thisinstance, the bowl unit may be arranged to be latched to the holdingtank in an assembled position in which the removable wall section isclamped between the holding tank and the removable wall section.

The bowl unit is preferably supported on the removable wall section withthe removable wall section being supported on the holding tank.

When the wall sections include a plurality of upright perimeter wallsections, the removable wall section preferably overlaps a top end ofthe perimeter wall sections about a full periphery of the wall openingto support the bowl unit thereon.

More particularly, the plurality of wall sections may comprise a bottomwall section, a plurality of upright side walls sections extendingupwardly from the bottom wall section about a periphery thereof andformed integrally therewith, and a top wall section spanning a wallopening defined at a top end of the holding chamber by the side wallsections, in which the top wall section comprises the removable wallsection.

The bottom wall section and the side wall sections are preferablygenerally flat and smooth.

The wall opening preferably fully spans a top end of the holding tank.

The removable wall section may be arranged to be frictionally engagedand retained within the wall opening. In this instance, the removablewall section is preferably arranged to frictionally engage innersurfaces of the holding tank about a full periphery of the wall opening.

The removable wall section may be arranged to be snap fit over the wallopening.

Connection between the valve mechanism and the inlet opening ispreferably stronger than connection between the valve mechanism and thedischarge opening such that a greater force is required to separate thevalve mechanism from the inlet opening of the holding tank than toseparate the valve mechanism from the discharge opening of the bowlunit.

Preferably the wall opening has an area which is plural times greater inmagnitude than an area of the inlet opening.

When the wall sections include a plurality of upright wall sectionsabout the wall opening, preferably at least a forwardmost one of thewall sections is generally curved about the wall opening.

The toilet may be provided in combination with a liner securable withinthe waste holding chamber about a periphery of the wall opening.

There may be provided a gauge supported on the holding tank and arrangedto visually indicate a volume of contents in the waste holding chamber.

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the portable toilet.

FIG. 2 is a perspective view of the portable toilet in which the bowlunit is shown separated from the holding tank and valve mechanism.

FIG. 3 is a sectional perspective view of the portable toilet in anassembled configuration.

FIG. 4 is a perspective view of the holding tank with the top wallsection separated therefrom.

FIG. 5 is a perspective view of the valve mechanism shown separated fromthe top wall section of the holding tank.

FIG. 6 is a front elevational view of the holding tank with the top wallsection shown separated.

FIG. 7 is a top plan view of the base of the holding tank.

FIG. 8 is a perspective view of the bowl unit with the seat and lidshown removed.

FIG. 9 is a front elevational view of the bowl unit according to FIG. 8.

FIG. 10 is a perspective view of the lid of the portable toilet.

FIG. 11 is a perspective view of the seat of the portable toilet.

In the drawings like characters of reference indicate correspondingparts in the different figures.

DETAILED DESCRIPTION

Referring to the accompanying figures there is illustrated a portabletoilet generally indicated by reference numeral 10. The toilet 10 isgenerally of the type in which a flushing fluid is used to flush wasteinto a waste holding chamber 12 which can be detached for subsequentdisposal of the waste therein.

The portable toilet includes a bowl unit 14 which is detachably mountedon a holding tank 16 so as to be selectively separable therefrom. Theholding tank 16 locates the waste holding chamber 12 therein.

The bowl unit includes a toilet bowl 18 which has an inner surfacetapering downwardly and inwardly from an upper rim 20 to a centraldischarge opening 22 defining a respective discharge rim 24 adjacent thebottom of the bowl unit. The toilet bowl 18 is surrounded by an annularreservoir 26 which receives the flushing liquid therein prior to its usefor flushing waste into the waste holding chamber. The bowl unitincludes an annular upright side wall 29 which defines an outer wall ofthe reservoir 26 while the inner wall of the annular reservoir isdefined by the generally conical surface of the toilet bowl 18. Agenerally flat annular top wall 30 and a generally flat annular bottomwall 32 enclose the top and bottom ends of the annular reservoir for theflushing liquid.

The bottom wall 32 of the bowl unit includes a peripheral shoulder 34about a periphery of the bowl unit to define a central lower steppedportion of the bottom wall 32 such that the shoulder 34 comprises agenerally annular, flat, horizontal bearing surface above the bottomwall 32, and at the perimeter of the bowl unit, which is suitablyarranged to be supported on the holding tank 16.

A toilet seat 36 is arranged to be supported on top of the bowl unit soas to be hinged at a rear side of the toilet in a generally conventionalmanner. The seat 16 has an annular configuration for being engaged uponthe annular rim 20 of the toilet bowl when pivoted into a horizontalin-use position. A toilet lid 38 is also hinged at the rear of the bowlunit to fully span the seat 36 to enclose the central opening thereof ina conventional manner.

The bowl unit also includes a fill port 40 onto which a screw cap may besecured to selectively enclose the fill port 40. When the screw cap isremoved, the fill port permits the flushing fluid to be replenished inthe annular reservoir 26 with which the fill port communicates. The fillport 40 is situated at a top end of the bowl unit, adjacent the hinge ofthe lid 38 at a rear end of the bowl unit.

A flush mechanism 42 is also provided on the bowl unit for communicationwith the flushing liquid in the annular reservoir to effectively pumpfluid from the reservoir and into the toilet bowl when actuated. Theflushing mechanism 42 may comprise any one of various conventionalflushing mechanisms available in the prior art relating to portabletoilets. In the illustrated embodiment, the mechanism 42 comprises amanually operated pump which serves to pump fluid from the reservoir 26through a flushing discharge tube 43 which discharges onto the innersurface of the toilet bowl 18 adjacent a top end thereof. The mechanism42 is situated on the top of the bowl unit adjacent the hinge of the lidat the rear end of the bowl on an opposing side of the bowl unitrelative to the fill port 40.

Upon a user manually pressing the flushing mechanism 42 at the top rearend of the bowl unit, flushing fluid from the reservoir 26 will bedispensed into the toilet bowl 18 for flushing waste downwardly into thedischarge opening.

The holding tank 16 generally includes a base 44 comprised of a bottomwall section 46 and a plurality of side wall sections 48. The side wallsections 48 are joined with one another to form a continuous annularwall joined with the bottom wall section 46 about the periphery thereofso that the bottom wall section 46 and the side wall sections 48together define an integrally injection moulded receptacle with a wallopening 50 spanning the open top end thereof between the generallyupright side wall sections 48. The side wall sections 48 are oriented ina near vertical orientation with a slightly upward and outward taperrelative to one another. The side wall sections 48 are joined with oneanother at rounded corners so that the wall sections together form asmooth continuous wall having a flat inner surface which is free of anyprotrusions or recesses upon which waste material may be caught orcollected.

A laterally protruding lip 52 is provided at the top end of the sidewall sections 48 to extend about a full periphery of the wall openingdefined at the top end of the base 44. The lip 52 provides somereinforcement to the top edge of the side wall sections while alsoproviding a suitable structure onto which a top wall section 54 may beadequately secured.

The upright side wall sections 48 at the front of the holding tank 16are arranged to form an arcuate path of generally semicircular shape asviewed from above so that the front portion of the holding tank forms aspout-like structure that functions as a suitable spout when dumping thewaste contents of the holding tank through the wall opening 50 definedas spanning the open top end of the holding tank when the removable topwall section 54 is separated from the side wall sections 48.

The top wall section 54 comprises a generally flat and rigid panel whichis arranged to fully span the top wall opening 50 of the holding tankfor enclosing the opening 50 while remaining selectively separable fromthe remaining wall sections 46 and 48 of the holding tank for access tothe holding chamber 12 defined within the interior of the holding tank16 as desired. The top wall section 54 includes a raised edge 56 aboutthe periphery thereof which is suitably sized so as to be snuglyfrictionally engaged within the wall opening 50 in the holding tank sothat the raised edge 56 of the top wall section 54 is in sealingengagement with the inner surfaces of the side wall sections 48 when thetop wall section 54 is mounted in use for enclosing the wall opening 50.

A peripheral lip 58 projects radially outward from the raised edge 56 ofthe top wall section 54 spaced above the main panel portion of the topwall section so that the peripheral lip 58 is suitably arranged tooverlap the top side of the lip 52 about a full periphery of the wallopening 50 in the holding tank 16.

An additional depending flange 60 is provided on the peripheral lip 58also about the full periphery thereof to extend downwardly from the lip58 spaced outwardly from the raised edge 56 so as to define a channelbetween the depending flange 60 and the raised edge 56 of the top wallsection 54 which snugly receives the lip 52 by friction fit therein. Thedepending flange 60 thus overlaps the outer side of the lip 52 about thewall opening 50 of the holding tank. The friction fit of the lip 52 ofthe holding tank received in the channel defined about the perimeter ofthe top wall section 54 provides a suitable seal between the top wallsection and the remaining wall section to prevent the escape ofsplashing fluids within the waste holding chamber 12 in the holding tankduring transport to a dumping location for discharging the contents ofthe waste holding chamber. In further embodiments, if desired a snap fitconnection may be provided between the wall section 54 and the side wallsections 48 of the holding tank for added securement and sealing duringtransport of the holding tank.

An inlet opening 62 is provided in the holding tank 16 by being locatedcentrally within the top wall section 54 so as to be centrally locatedat the top end of the holding tank 16. The inlet opening 62 issurrounded by an upright collar 64 projecting upwardly from the panelportion of the top wall section to define an externally threaded portionabove the panel portion while also extending downwardly slightly belowthe panel portion of the top wall section 54 to define a stem portionbelow the panel portion. The inlet opening 62 is suitably sized andlocated for alignment in cooperation with the discharge opening 52 ofthe bowl unit when the peripheral shoulder 34 of the bowl unit isengaged upon the top of the side wall sections 48 of the holding tankwith the peripheral lip 58 of the top wall section 54 securedtherebetween.

A valve mechanism 66 is associated with the inlet opening forcontrolling opening and closing of the inlet opening and accordingly forcontrolling communication between the discharge opening 22 of the toiletbowl and the waste holding chamber 12 of the holding tank through theinlet opening of the tank. The valve mechanism 66 generally comprises avalve body 68 in the form of a collar which is internally threaded at alower end so as to be arranged for threaded connection with theexternally threaded portion of the collar 64 about the inlet opening 62.An opposite end of the valve body 68 includes a counterbore 70 thereinso that the counter bore faces upwardly in the mounted and in useposition. The counterbore 70 is suitably dimensioned to snugly receivethe discharge rim 24 of the discharge opening 22 in frictional sealingengagement therein.

A valve member 72 is mounted within the valve body 68 in the form of agenerally circular plate member which is supported for sliding movementgenerally horizontally in relation to the valve body 68 betweenrespective closed and open positions. In the closed position the valvemember 72 spans across the inlet opening for sealing the inlet openingclosed with a suitable sealing member. In the open position, the valvemember 72 is horizontally displaced so as to be substantially removedfrom the inlet opening so that the inlet opening is substantiallyunobstructed in relation to the closed position of the valve member. Anactuator stem 74 projects radially outward from the valve body 68 forreceiving the valve member 72 in the open position. The valve member 72is connected through the stem 74 to an actuator handle 76 at the outerfree end of the actuator stem 74. The handle 76 may be manually graspedby a user of the toilet to displace the valve member 72 between theclosed and open positions. Biasing means are provided to bias the valvemember to the closed position.

A suitable channel 78 is formed in the bottom wall of the bowl unit toextend between the discharge rim 24 of the toilet bowl and the outerside wall 28 of the bowl unit. The channel comprises a raised portion ofthe bottom wall of the bowl unit arranged for receiving the actuatorstem 74 extending between the discharge rim 24 and the outer side wall28. At the outer side wall 28, the bottom wall is recessed upwardly intothe bowl unit at the channel 78 sufficiently to receive the handle 76 atthe outer end of the stem 74. The user can thus operate the valve memberby gripping the handle 76 at the outer side of the bowl unit anddisplacing the handle radially outward to open the valve member orradially inward to close the valve member.

The discharge rim 24, at the bottom end of the downward and inwardtapering surface of the bowl 18, is spaced upwardly from the bottom wallsection 54 to provide sufficient clearance for the valve body betweenthe removable top wall of the holding tank and the reservoir. Thechannel 78 thus also defines walls of the reservoir 26 which spanbetween the bottom wall section 54 and the discharge rim 24 which israised upwardly in relation to the bottom wall section 54. The dischargerim 24 also includes a collar portion extending downward from the topside of the channel 78 for engagement within the counterbore 70 in thevalve body.

A latching mechanism is provided for securing the bowl unit to theholding tank when the bowl unit is supported thereon. The latchingmechanism generally comprises two anchor bodies 80 supported on opposingside wall sections 48 of the holding tank by being integrally formedtherewith. Link arms 82 are pivotally connected on the anchor bodies 80respectively onto which a pair of latch members 84 are respectivelypivotally mounted. Each latch member 84 includes a hook at a free endthereof for engaging a respective shoulder 86 formed on the side walls28 of the bowl unit in alignment with the latch members when the bowlunit is supported on the holding tank. Operation of the latch membersbetween respective engaged/latched positions and respective releasedpositions is generally conventional. In alternative embodiments, thelatch members may instead be pivotally supported on the bowl unit forengaging respective shoulders on the holding tank if desired.

Prior to assembling all of the components of the toilet, gaskets 90 areprovided at various locations to provide sealing engagement betweenholding tank and the removable top wall section, between the valvemechanism at the opening in the removable top wall section at plurallocations, and between the discharge opening of the toilet bowl and thevalve mechanism at plural locations. Each gasket 90 comprises an annularresilient sealing member arranged to be compressed between respectivecomponents where relative sealing engagement is desired.

More particularly, two gaskets 90 are provided at axially spacedpositions at opposing ends of the threaded connection between the valvebody and the inlet opening in the removable top wall. Both gaskets 90thus extend about the collar 64 above the top wall section to becompressed between the collar 64 and the valve body 68 secured thereto.

Two other gaskets 90 are provided about an inner surface and an outersurface respectively of the valve body 68 adjacent the top end thereoffor engagement with respective mating surfaces of the channel 78 and thedownward projecting collar portion of the discharge rim 24 in the bottomwall of the bowl unit. The gaskets 90 in this instance seal engagementbetween the collar portion of the discharge rim and the counterbore inthe valve body receiving the collar portion therein.

An additional one of the gaskets 90 is provided about the peripheral lip52 of the holding tank upon which the peripheral lip 58 of the top wallsection is sealably engaged.

In use, the components are assembled such that the top wall sectionthreadably secures the valve body of the valve mechanism thereon. Thetop wall section is in turn frictionally engaged into the wall opening50 defined by the remaining wall sections to fully enclose the wasteholding chamber 12 within the holding tank 16. The peripheral shoulder34 about the bottom of the bowl unit is then aligned with the top edgeof the upright wall sections 48 for supporting the bowl unit thereon. Insupporting the bowl unit onto the holding tank, the depending collarportion of the discharge rim of the toilet bowl is also aligned andfrictionally engaged into the counterbore in the top end of the valvebody 68 for sealing engagement therebetween. The latch members 84 onopposing sides of the holding tank can then be pivoted into latchingengagement with the respective shoulders on the bowl unit for clampingthe bowl unit to the holding tank. In doing so the top wall section 54is effectively clamped between the bowl unit and the holding tank sothat the top wall section 54 of the holding tank is clamped down to theside wall sections 48 commonly by the latch members 84 which also serveto secure the bowl unit to the holding tank.

When a person uses the portable toilet, the flush mechanism works as inconventional flushing mechanisms for portable toilets to provide aflushing liquid from the reservoir into the toilet bowl. The valvemember 72 is then displaced into the open position using the handle 76communicating with the valve member 72 through the actuator stem 74 soas to be arranged for manually operation by the user. Releasing thehandle 76 causes the valve member 72 to be biased back into the closedposition for sealing the holding chamber 12 within the holding tankclosed.

When it is desired to empty the contents of the waste holding chamber12, releasing the latch members 84 permits the bowl unit to be readilydetached and separated from the holding tank simply by lifting the bowlunit up off of the holding tank. The threaded connection between thevalve body and the collar about the inlet opening in the top wallsection 54 ensures that the valve mechanism remains closed across theinlet opening when the bowl unit is released therefrom. The press fit orfrictional engagement of the top wall section 54 to the side wallsections 48 is a tighter fit over a larger area as compared toconnection between the discharge rim 24 of the toilet bowl and thecounterbore of the valve mechanism to ensure that when the bowl unit islifted from the holding tank, the bowl unit releases from the valvemechanism and the top wall section 54 remains snugly engaged to span theopen top end of the holding tank.

When it is desired to dump the contents of the holding tank, the holdingtank can be transported by itself apart from the bowl unit whileremaining in a sealed and enclosed configuration throughout transport toa dumping location. Once ready to discharge the contents, the top wallsection can be readily removed and the waste material within the wasteholding chamber 12 can be poured out using the spout like configurationof the curved front side wall section 48 of the holding tank.

In some instances it may be desirable to use a liner bag 90 as shown inFIG. 6 which can be used to line the bottom wall section 46 and the sidewall sections 48 so as to be secured about a periphery of the wallopening 50 of the holding tank between the top wall section 54 and theside wall sections in use.

In other embodiments, a translucent gauge strip 92 may be formed in oneof the side wall sections of the holding tank to permit a user to gaugea level of waste material in the waste holding chamber of the holdingtank. In yet further embodiments, the gauge strip may be replaced withother types of gauges including float sensors and/or dial gauges and thelike.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of same madewithin the spirit and scope of the claims without department from suchspirit and scope, it is intended that all matter contained in theaccompanying specification shall be interpreted as illustrative only andnot in a limiting sense.

1. A portable toilet comprising: a bowl unit comprising a toilet bowlwith a bottom discharge opening and a reservoir arranged to receive aflushing liquid for flushing the toilet bowl; a holding tank arranged tosupport the bowl unit thereabove, the holding tank defining a wasteholding chamber enclosed by a plurality of wall sections; an inletopening in an upper one of the wall sections of the holding tank whichis arranged to co-operate with the discharge opening of the toilet bowlwhen the bowl unit is supported on the holding tank such that wastematerial in the toilet bowl is arranged to be received through the inletopening into the waste holding chamber; and a valve mechanism associatedwith the inlet opening of the holding tank, the valve mechanismcomprising a valve member operable across the inlet opening betweenrespective open and closed positions; one of the wall sections of theholding tank comprising a removable wall section which is selectivelyseparable from remaining ones of the wall sections such that theremaining ones of the wall sections define a wall opening in the holdingtank through which waste material in the waste holding chamber isarranged to be discharged.
 2. The toilet according to claim 1 whereinthe removable wall section comprises an uppermost one of the wallsections which spans a top end of the holding tank.
 3. The toiletaccording to claim 1 wherein the removable wall section locates theinlet opening therein.
 4. The toilet according to claim 1 wherein theremovable wall section is held in a closed position spanning the wallopening by the bowl unit supported on the holding tank.
 5. The toiletaccording to claim 1 wherein the bowl unit is arranged to be latched tothe holding tank with the removable wall section clamped between theholding tank and the removable wall section.
 6. The toilet according toclaim 1 wherein the bowl unit is supported on the removable wall sectionand the removable wall section is supported on the holding tank.
 7. Thetoilet according to claim 1 wherein the wall sections include aplurality of upright wall sections and the removable wall sectionoverlaps a top end of the wall sections about a full periphery of thewall opening.
 8. The toilet according to claim 1 wherein the pluralityof wall sections comprise a bottom wall section, a plurality of uprightside walls sections extending upwardly from the bottom wall sectionabout a periphery thereof and formed integrally therewith, and a topwall section spanning a wall opening defined at a top end of the holdingchamber by the side wall sections, the top wall section comprising theremovable wall section.
 9. The toilet according to claim 8 wherein thebottom wall section and the side wall sections are generally flat andsmooth.
 10. The toilet according to claim 1 wherein the wall openingfully spans a top end of the holding tank.
 11. The toilet according toclaim 1 wherein the wall sections include a plurality of upright wallsections upon which the bowl unit is arranged to be supported.
 12. Thetoilet according to claim 1 wherein the removable wall section isarranged to be frictionally engaged within the wall opening.
 13. Thetoilet according to claim 12 wherein the removable wall section isarranged to frictionally engage inner surfaces of the holding tank abouta full periphery of the wall opening.
 14. The toilet according to claim1 wherein the removable wall section is arranged to be snap fit over thewall opening.
 15. The toilet according to claim 1 wherein frictionalconnection between the valve mechanism and the inlet opening is arrangedto be stronger than connection between the valve mechanism and thedischarge opening.
 16. The toilet according to claim 1 wherein the wallopening has an area which is plural times greater than an area of theinlet opening.
 17. The toilet according to claim 1 wherein the wallsections include a plurality of upright wall sections about the wallopening and wherein at least one of the wall sections is generallycurved about the wall opening.
 18. The toilet according to claim 1 incombination with a liner securable within the waste holding chamberabout a periphery of the wall opening.
 19. The toilet according to claim1 wherein there is provided a gauge supported on the holding tank andarranged to visually indicate a volume of contents in the waste holdingchamber.
 20. A portable toilet comprising: a holding tank defining awaste holding chamber surrounded by a plurality of wall sections; a bowlunit arranged to be supported above the holding tank comprising a toiletbowl with a bottom discharge opening; an uppermost one of the wallsections of the holding tank comprising a removable wall section whichis selectively separable from remaining ones of the wall sections suchthat the remaining ones of the wall sections define a wall opening inthe holding tank spanning the top end of the holding tank through whichwaste material in the waste holding chamber is arranged to bedischarged; the uppermost one of the wall sections having an inletopening therein which is arranged to co-operate with the dischargeopening of the toilet bowl when the bowl unit is supported above theholding tank such that waste material in the toilet bowl is arranged tobe received through the inlet opening into the waste holding chamber;and a valve mechanism associated with the inlet opening of the holdingtank, the valve mechanism comprising a valve member operable across theinlet opening between respective open and closed positions.